Mass = molarity x molar mass( NaNO₃) x volume
mass = 1.50 x 85.00 x 4.50
mass = 573.75 g of NaNO₃
hope this helps!
F (Fluorine) is in column (group/family) VIIA, or the "halogens". When you see the halogens (Fluorine, Chlorine, Bromine, and Iodine) in combination with a metal, each halogen atom present will carry a -1 charge. We can see that the atom has no charge, so the metal must cancel out the negative charges brought by the two fluorine atoms.
(Charge on m) + 2*(charge on fluorine) = 0
(Charge on m) + 2*(-1) = 0
(Charge on m) - 2 = 0
Charge on m ion = +2
Molar mass H₃PO₄ = 98.0 g/mol
1 mole ----- 98.0 g
? mole ------ 30.0 g
moles = 30.0 * 1 / 98.0
= 0.306 moles
hope this helps!